function encryptByte(self, byteParam, decrypt) {
    var pad = self._cipher.encryptBlock(self._prev);
    var out = pad[0] ^ byteParam;
    self._prev = Buffer.concat([
        self._prev.slice(1),
        Buffer.from([decrypt ? byteParam : out])
    ]);
    return out;
}
export const encrypt = function (self, chunk, decrypt) {
    var len = chunk.length;
    var out = Buffer.allocUnsafe(len);
    var i = -1;
    while (++i < len) {
        out[i] = encryptByte(self, chunk[i], decrypt);
    }
    return out;
};
